For CTLA4, CD4+ T cells were the most expressed, significantly higher than the second CD8+ T cells, and the expression of the rest of the cells was low, but epithelial cells and fibroblasts in lung cancer also expressed CTLA4 higher, which was not observed in breast cancer and colorectal cancer (Figures 4B, 5B, 6B). Here, CD4 is linked to breast carcinoma.